1. Field of the Invention
The present invention relates to a method of producing retort food comprising animal meat such as beef or pork, or fish meat such as horse mackerel, spanish mackerel, bonito, or tuna, which meat is broiled with soy sauce and packaged.
2. Prior Art
The technique of retort sterilization processing various foods after they have been packed and sealed, thereby to improve the storability of the foods, in retort containers, has conventionally been known. Specifically, various foods such as cooked curries, soups and stews are widely sold as retort food. The number of types of foods packed in retort containers are subjected to retort processing increases every year. In addition, techniques of retort sterilization processing broiled foods have been proposed. For example, Japanese Patent Publication No. 54-37214 discloses that a cut eel is broiled and then dried until the surface of the eel hardens in order to be vaccum-packaged, and Japanese Patent Publication No. 57-33010 discloses that a meat or fish is charged in a bag and thereafter the air in the bag is replaced by a carbon dioxide gas or a mixture of carbon dioxide and nitrogen gas to subject it to sterilization processing. Fathermore, Japanese Patent Unexamined Publication (KOKAI) No. 59-166061 discloses that a dried fish is immersed in a seasoning solution, broiled and vacumm-packaged, and Japanese Patent Unexamined Publication No. 55-150879 also discloses that a flatfish is immersed in a seasoning solution, slightly dried, and vaccum-packaged to subject it to high pressure (1.5-2 atoms) - heat (110.degree.-120.degree. C.) treatment.
However, since retort sterilization is a method in which cooked food is put in a high-pressure sterilizing pot after the food has been enclosed and sealed within a retort container, and in which the food is sterilized under pressure at a high temperature of not less than 100.degree. C., there is a risk that some types of foods may become discolored, generate an offensive smell, or have an unpleasant taste. In particular, when broiled meat or meat broiled with soy sauce (hereinafter generically referred to as "soy-broiled meat"), which is cooked either by broiling the meat after it has been soaked in soy sauce or by broiling the meat while soy sauce is added thereto, is subjected to retort processing so as to produce retort food, there has been encountered a problem in that the meat may brown considerably during the retort processing or the meat may have an unpleasant bitter taste.